There are a number of instances in which it may be desirable to have a simple indication of the status of an electrical connection to a computer, a computer peripheral, computer network or to instrumentation, telecommunications, inspection or a similar device or network. Indicators of this type are especially useful for products such as networking hubs, switches and routers. A simple visual indication provided by an LED located adjacent to an input/output connector is often desirable. For example, an indication that a device, or its input cable, has been properly wired or connected is helpful to insure proper installation. A flashing LED is often useful as a means to show that communications is occurring on that circuit. This visual indicator can help a user diagnose a problem without requiring the assistance of a specialist. For example, the absence of a flashing indicator on a modem will show that communication has not been properly established or that a connection has been lost.
One traditional approach to insuring that a device, a cable or a network has been properly wired, connected or assembled is the use of a standalone testing device. Elimination of this separate testing device by incorporating an LED or other indicator, visual or otherwise, in the component itself has advantages, not only during installation, but during operation of the device. However. the addition of LED's or other indicators to an already crowded device does pose space problems. One approach that has been suggested is to add the LED on the front or mating face of the electrical connector to save printed circuit board real estate.
Several patents show suggestions for incorporating LED's on the mating face of a modular jack, and especially on the front of an RJ-45 eight position modular jack. U.S. Pat. No. 4,978,317 shows an RJ-45 jack with two light emitting diodes mounted on the mating face of the jack. In this patent the LED's are mounted along the side of the jack mating opening opposite from which the mating ends of the terminals are attached. To connect the LED's to a printed circuit board, mounted along an opposite surface of this single position jack housing, the LED leads must extend around two sides of the jack and protrude from the printed circuit board mounting face of the jack. These LED leads appear to require a length that is greater than the length of leads typically employed for many through hole LED's. For multiple position or stacked jacks, the LED lead length would have to be even greater for a device constructed in this manner.
U.S. Pat. No. 5,601,451 shows another approach in which the LED's are mounted adjacent to the printed circuit board. Clearly however, this approach is limited to a single position modular jack and does not offer a solution to providing multiple LED's for each of multiple jacks mounted in a stacked configuration or included in a single housing mounted on the edge of a printed circuit board.
Another approach is the use of surface mount LED's located below a printed circuit board housing, but that approach requires that both surface mount components and through hole components be used on the same printed circuit board, if standard through hole modular jacks are to be employed. This approach can cause problems or can require additional care during the soldering operation to insure that satisfactory through hole and surface mount solder joints are established on the same board. Through hole jacks mounted above surface mount LED's can leave the surface mount joints unexposed, thus leading to unreliable solder joints. Dual processing for the through hole jack leads and the surface mount LED's would probably be necessary.
Still another approach that has been suggested is the use of LED's mounted on upstanding flexible films that are mounted on a printed circuit board in front of the connector or jack. This requires the addition of a separate piece and requires the film be positioned in registry with the mating openings in a printed circuit board. Separately mounting component in this manner is further complicated when stacked connectors, employing jacks stacked one above the other, are employed.